When a Similarity Report is available for viewing, a similarity score percentage displays in your assignment inbox.
Understanding Similarity report
The similarity score does not necessarily reflect the percentage of plagiarized content. It may include correctly cited and quoted material. This number simply shows the extent to which the paper matches content from external sources.
Regardless of the similarity index, you will need to analyze the report to determine whether the student plagiarized. If the reference list is very long, you can exclude it as well as short phrases to bring the number down. Below the similarity number will be all the sources to which parts of the paper matched. There is a number next to each which tells you how much of the paper came from that source.
Source: Turnitin page - https://guides.turnitin.com/hc/en-us/articles/23435833938701-Understanding-the-Similarity-Score
